I am pretty sure that hte answer is A. I am not completely sure, I hope this helps
Answer:
<u><em>Mất khoảng 1 năm thì khăn giấy mới phân hủy được</em></u>
Explanation:
Uranium-238 is found only in igneous or volcanic rocks. They can date a very ancient fossil also but carbon cannot date and ancient fossil. Trees are not very ancient. Carbon-14 can be used to measure only fossils of recent age.
The observer will see the paper clip in 3